Liner dependence between cohesive and surface free energy, and further consequently adsorptive strength of intermediates (M-H), along with volcano plots for electrocatalytic activity in hydrogen electrode reactions led us to interrelate them and define optimal synergistic activity features. Since the electrocatalytic activity plot along every hypo-hyper-d-d-interelectronic phase diagram behaves as along the part of the Periodic Table between the two periods of these interacting constituents, with intermetallic phases replacing the missing elements in between, such an approach leads us straight to define optimal composite catalysts for the HER, their synergistic d-electronic configuration, the position of the center of the anti-bonding peak relative to the Fermi level, and other relevant parameters of advanced peak-position electrocatalysts. In the same sense, electron-conductive and the d-d-interactive hypo-d-oxides (titania, tungstenia) and suboxides (Magneli phases) have been introduced in electrocatalysis as the interactive supports featuring the SMSI (Strong Metal-Support Interaction) properties: (i) The stronger the d-d-interelectronic bonding, the less strong arises the intermediate adsorptive bond in the RDS, and consequently, the higher the reaction rate or electrocatalytic activity; and (ii) Since hypo-d-oxides behave as the altervalent exchange membranes, the overall transferring effect under the directional field of polarization is the resulting spillover or effusion of the primary oxide (M-OH), which is decisive for the cathodic oxygen reduction (ORR) and CO tolerance, and traced the path towards the nearly reversible oxygen electrode and some other advanced nanostructured bronze, and to novel interactive supported nanosized hyper-d-oxide catalysts both for the ORR and ORR in so called revertible cells.